This invention relates to a method and an arrangement for recognizing potential overheating of an object.
Overheating of objects is a general problem caused e.g. by heat generation on the outside of the object (e.g. by fire) or by internal heat generation e.g. in machines, engines or components.
Examples of this are engines in operation, e.g. internal combustion engines or thrusters, which are operated with combustible liquids or gases. In such engines there is a potential risk of fire when they have defects. Particularly in the aviation technology it is, in the case of fire, very important to bring the fire under control as fast as possible and, thus, to prevent the engine from being destroyed. This can be effected e.g. by interrupting fuel supply in time. This interruption can be effected by hand by means of a fuel shut-off by an electromechanical valve.
Several methods or measures are known, which consider a possible overheating of an object. By one kind of methods or measures the object is protected from being overheated (i.e. overheating is prevented), e.g. by a fireproof casing or by cooling. By means of other kinds of methods or measures the possible overheating is recognized and suitable measures are then carried out, by which the overheating is prevented or the dangers caused by the overheating are eliminated or reduced. Such measures are e.g. interruption of the fuel supply to an engine in the case of fire or interruption of the power supply of a component.
In order to effectively react to overheating, it is favorable to recognize the risk of overheating in good time.
It is therefore an object of the present invention to provide an effective method and an effective arrangement for recognizing in good time a potential overheating of an object.
According to the invention, this object is achieved by a method for recognizing potential overheating of an object, by which method the temperature of the object is measured and temperature values of the object are determined. These temperature values are used to determine the temperature gradient. The thus calculated value of the temperature gradient is compared with a predetermined value. In dependence on this comparison of the determined value of the temperature gradient with the predetermined value, a warning signal is triggered.
According to the invention, this object is furthermore achieved by an arrangement for recognizing potential overheating of an object, the arrangement comprising at least one temperature sensor for measuring the temperature of the object. Signal processing means determine the temperature gradient from the temperature values measured by the at least one temperature sensor. Comparator means then compare the determined value of the temperature gradient with a predetermined value and output a comparator signal. In dependence on this comparator signal, warning signal generating means trigger a warning signal.
The invention is based on the idea that a potential overheating of an object can be recognized very early by making use of the temperature gradient. Then, the overheating can be recognized even before it actually appears. This can be done by comparing the determined temperature gradient with a threshold value which may be individually defined for the object in question. If this threshold value is exceeded it can be concluded that there is a risk of overheating of the object. Then, by an indicating of this exceeded value, suitable measures can be carried out.
This method and this arrangement according to the invention can e.g. be used for recognizing fire or as overheating protection of components.
In one aspect of the invention the method and the arrangement is applied to an engine having fuel supply, the protective measures consisting in interrupting the fuel supply.
Further objects and features of the invention will be apparent to a person skilled in the art from the following specification of a preferred embodiment when read in conjunction with the appended claims.